diff --git a/umap/static/umap/base.css b/umap/static/umap/base.css
index 05af31bf..5bc48647 100644
--- a/umap/static/umap/base.css
+++ b/umap/static/umap/base.css
@@ -669,6 +669,11 @@ input[type=hidden].blur + .button {
     /*box-shadow: inset 0 0 0 1px #215d9c;*/
     color: #efefef;
 }
+input:invalid {
+    border-color: red;
+    background-color: darkred;
+}
+
 
 /* *********** */
 /*   Alerts    */
diff --git a/umap/static/umap/js/umap.js b/umap/static/umap/js/umap.js
index 27414e33..8537819e 100644
--- a/umap/static/umap/js/umap.js
+++ b/umap/static/umap/js/umap.js
@@ -14,6 +14,7 @@ L.Map.mergeOptions({
   default_popupContentTemplate: '# {name}\n{description}',
   default_interactive: true,
   default_labelDirection: 'auto',
+  maxZoomLimit: 20,
   attributionControl: false,
   allowEdit: true,
   embedControl: true,
@@ -1524,11 +1525,21 @@ L.U.Map.include({
       ],
       [
         'options.tilelayer.maxZoom',
-        { handler: 'BlurIntInput', placeholder: L._('max zoom') },
+        {
+          handler: 'BlurIntInput',
+          placeholder: L._('max zoom'),
+          min: 0,
+          max: this.options.maxZoomLimit,
+        },
       ],
       [
         'options.tilelayer.minZoom',
-        { handler: 'BlurIntInput', placeholder: L._('min zoom') },
+        {
+          handler: 'BlurIntInput',
+          placeholder: L._('min zoom'),
+          min: 0,
+          max: this.options.maxZoomLimit,
+        },
       ],
       [
         'options.tilelayer.attribution',
@@ -1563,11 +1574,21 @@ L.U.Map.include({
       ],
       [
         'options.overlay.maxZoom',
-        { handler: 'BlurIntInput', placeholder: L._('max zoom') },
+        {
+          handler: 'BlurIntInput',
+          placeholder: L._('max zoom'),
+          min: 0,
+          max: this.options.maxZoomLimit,
+        },
       ],
       [
         'options.overlay.minZoom',
-        { handler: 'BlurIntInput', placeholder: L._('min zoom') },
+        {
+          handler: 'BlurIntInput',
+          placeholder: L._('min zoom'),
+          min: 0,
+          max: this.options.maxZoomLimit,
+        },
       ],
       [
         'options.overlay.attribution',